PAC, with its convenient graphical connection manager, is a Linux application that manages SSH and other connections. The tool supports macros and lets users send commands to an entire cluster of servers simultaneously.

Even tried and trusted configurations that have proved their value through the years can be tripped up by special cases – for example, all of your users logging in with the same IP address. Experienced administrators and Bash aficionados will then enable debugging and launch a systematic search for configuration errors.